Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Difficulties with the QPOs Difficulties with the QPOs resonance modelresonance model

by Paola Rebusco

Jean-Pierre Lasota’s Birthday Conference 2007

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Lekcja pierwsza

Wiedzieć, że wiemy to co wiemy i wiedzieć, że nie wiemy tego czego nie

wiemy, oto prawdziwa wiedza.

Mikołaj Kopernik

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

First Lesson

Wiedzieć, że wiemy to co wiemy i wiedzieć, że nie wiemy tego czego nie wiemy, oto prawdziwa wiedza.

Mikołaj Kopernik

To know that we know what we know, and to know that we do not know what we do not know, that is true knowledge.

Nicolaus Copernicus

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

High frequency (kHz) QPOs

In Black Holes: stable

In Neutron Stars: the peaks move-much

more rich phenomenology (state, spin, Q)

T

. Str

ohm

ayer

20

01

M

. van d

er

Klis

20

00

1/M scaling -> orbital motion

3:2…although not always

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Difficulties according to…

“I do not believe in your model”Jean-Pierre Lasota

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Difficulties according to…

Outsiders: Tomaso Belloni

Insiders: A&K Team

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Outsiders

1)NEUTRON STARS“The biggest limit of the model is that it does

not work” T.B.

The two frequencies are in 3:2 ratio, but they are related in such a way that they move away from the 3:2 ratio.

= spin or spin/2 (NO!Mendez&Belloni 2007) No explanation of the direct observables (NO

MODEL DOES)

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

What is wrong with the Bursa line?

(32)(3+2)=65!

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Weakly nonlinear coupled oscillators

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Perturbed geodesics (numerics&theory)

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

BUT…

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Outsiders

2)BLACK HOLESStable3:2, [ GRS 1915+150 (5:3)..]

“on those small numbers” (4) “the model works”TB

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Insiders - BH vs NS

Different modulation (see Michal Bursa’s talk)

Different excitation

Different mechanism (Outsider)?

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Insiders- SIMULATIONS

Slender tori slightly out of equilibrium do not produce QPOs (only transient - Mami Machida)

They do if the torus is kicked HOWEVER it is difficult to recognize

the modes

(Omer Blaes, Chris Fragile, Mami Machida, Eva Sramkova)

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Insiders - EXCITATION MECHANISM

Direct forcing (NS rotation?but spin)

Stochastic forcing (BH?)

Disk instabilities (Mami Machida’s simulations: P&P instability)

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Turbulence? (Vio et al 2005)

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

The “right” turbulence feeds the resonance

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Insiders - DAMPING

Stochastic damping ?!?

What controls the coherence Q= /? Didier Barret et al. - Qlow>Qhigh

- Qlow increases with

and drops

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Insiders - EPI or NOT EPI?!?

EPI: - Pressure and gravity coupling? NO!!! (slender torus-Jiri Horak)… the advantage is that they survive to damping - non axisymmetric modes?NONOT EPI: - the eigenfreq. depend on thermodynamics -> 1/M ?!? - g-modes (but do not survive) which modes are special?

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Modes and Spin (A&K, Michal Bursa, Eva Sramkova, Odele Straub)

Kerr geometry

Method 1= Ramesh Narayan group

Method 2= Middleton Group

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

Is it the end?

Thin disks

Non - constant l

a and

Paola Rebusco --- Jean-Pierre Lasota’s Bday 2007

HAPPY BIRTHDAY